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B. WESTON.

MANUFACTURE OF INGANDBSGBNTS. No. 310,761. Patented Jan. 13, 1885.

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EDWVARD \VESTON, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

MANUFACTURE OF ENCANDESCENTS.

SPECIFICATION forming part; of Letters Patent No. 310,761, dated January 13,1885.

Application filed November 20, 1883.

T0 etZZ whom it may concern:

Beit known that I, EDWARD Wnsron, asub ject of the Queen of Great Britain, and aresident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in the Mannfacture of Carbon Conductors, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.

My present invention consists in an improved process of manufacturing carbon conductors for incandescent lamps, the object of the invention being to produce conductors of considerable length that may be used in globes of small size. I have found that these objects are best obtained by conductors in the form of spirals, and my invention will be described as applied to the manufacture of this form, though from the nature of the process employed it will appear that the same is generally applicable to the mahufacture of any conductors of irregular conformation.

In carrying out my invention I proceed as follows: I cut from sheets of the desired materialsuch as paper, amorphous cellulose, orv the likestrips'or blanks. These blanks are then bent to the shape required for the completed carbon, and in'this condition exposed to a moderatelyhigh temperature, one just sufficient to set their shape. They are then placed in a muffie or retort and carbonized.

In order to impart to the blanks the required shape, I prefer to wind them upon mandrels-'such as rods or plates of any proper material-securing their ends by means of clamps, and expose them, while thus secured, to a temperature sufficiently high to fix their shape, so that when removed from the mandrels they will retain their spiral form- A small quantity of flaky plumbago is placed in the bottom of a common muffle, and upon this a number of the spirals are laid. These are then buried or packed in loose plumbago and a cover placed over them, which is supported so as not to press upon or compact the plumbago. Another layer of plumbago and blanks may be-placed above the first, and so on. The

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muffle, with its contents, is then placed in a carbonizing-furnace and exposed. to the heat until the blanks are carbonized. This process obviates many of the difficulties heretofore encountered in carbonizing blanks of irregular conformation by packing them in powdered carbon. It is understood that during carbonization a considerable shrinkage of the blanks takes place. I have found that the loose or powdered carbon which is usually employed-for instance, retortcarbon-does not permit this shrinkage to take place properly, 6c so that the conductors come from the muffle broken or distorted in shape and unfit for use. By using flaky plumbago for this purpose these objections are not met with. The conductors contract or shrink evenly and retain a perfect spiral. form. The conductors, subsequently to their oarbonization, may be treated in any of the usual ways and placed in the lamps.

In the drawings I haveshown simple and convenient means for carrying out the invention.

Figure 1 is a view of a mandrel or bar, A, with the blank 13 wound spirally thereon. O O are clamps to hold the ends in place. Fig.

2 is a sectional view of the muffle, illustrating the method of packing the blanks.

D is the muffle or box; E, the first layer of plumbago with blanks buried therein. F are carbon or metal bars, upon which a cover, G, of metal or carbon, is laid. E is the next layer of plumbago, similar to the first. More layers may be used when the depth of the muffle admits of it. It is obvious that this method is applicable to the manufacture of any conductors of irregular shape, such as those hav ing the form of loops, rings, or the like.

I am aware that blanks for the conductors of incandescent lamps have been packed or covered with powdered carbon and baked or carbonized, and such I do not claim, broadly; but, without confining myself to any special apparatus, or to the exact form of conductor,

WVhat I claim is- 1. The method or process of preparing conductors forincandescent lamps, which consists 5 in winding the blanks upon mandrels and baking them to set or fix their shape, then pack- W'ithflaky plumbago, and carbonizing them, in ing them in a muffle with flaky plumbago, and substantially the manner herein set forth. 1.0 carbonizing them, in substantially the manner In testimony whereof I have hereunto set my set forth. hand this 17th day of November, 1883.

2. The method of manufacturing carbon EDWARD WESTON. conductors of irregular shape, and adapted for Witnesses: use in incandescent lamps, which consists in HENRY A. BEOKMEYER, packing blanks cf the desired shapein a muffle PARKER WV. PAGE. 

